• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    PURPOSE: A print system and method are provided to identify a printing device on which a medium was printed by using encoded forensic markings which identify the device but are of low perceptibility to the human eye are superimposed on the printed image. CONSTITUTION: The method comprises steps of encoding system information identifying a printer into an information marker(S102), calculating a checksum for the information marker(S104), encoding the checksum into a checksum marker(S106), adding to each forensic marking at least one location marker indicative of a location of the forensic marking on the print medium(S108), adding to each forensic marking at least one camouflage marker indicative of randomized data such that the visibility of the forensic marking due to replication on the print medium is reduced(S118), rotating some of the individual one of the one forensic marking by a multiple of 90 degrees prior to the printing(S120), superimposing onto source data at least one encoded forensic marking containing the information marker and the checksum marker in order to create output data corresponding to the forensically marked image(S122), and printing the output data on a print medium in order to produce the forensically marked image, the forensic marking printed using a predetermined color difficult to detect by the human eye, but readily detectable by electronic scanning in order to identify the system(S124).
    公开号:KR20010090779A
    申请号:KR1020010018605
    申请日:2001-04-09
    公开日:2001-10-19
    发明作者:반류에드워드제이；나단노부코엠；우르피나비르센
    申请人:파트릭 제이. 바렛트；휴렛-팩커드 컴퍼니(델라웨어주법인)；
    IPC主号:
    专利说明:

    Printing system and method, device determination system {HIGH RELIABILITY FORENSIC COLOR MARKING SYSTEM}
    [15] BACKGROUND OF THE INVENTION Field of the Invention The present invention generally relates to printing with a color printing system, and more particularly, to a forensic marking system for color printers that accurately identifies a printer to which an output is printed while minimizing the perception of forensic marking to the human eye. will be.
    [16] Over the past few years, the quality of color images generated by computer printers, such as inkjet printers and color laser printers, has been improved to a degree comparable to the quality of images achievable by color photography. In addition, many such printers are capable of printing on a wide variety of media, including paper materials of various qualities, sizes and thicknesses. When an optical scanner is used in combination with a printer and a suitable print media, the original document can be scanned and printed to produce copies that are indistinguishable from the original. The scanner may be a separate peripheral device or may be combined with a printer in a single “all in one” peripheral device such as Hewlett Packard Company's OfficeJet ™ Pro Series product line, the assignee of the present application. “All-in-one” devices that may be connected to a computer or used as a standalone color copier that do not require an attachment computer commonly include an inkjet based printing system having a removable printer cartridge. Others have laser printing based systems. In addition, an optical scanning system is provided. The user scans the document with the scanning system and then prints the document with the printing system. In addition, the image information can be transmitted to and received from the attached computer. In some examples, a modem is provided that allows scanned text and other images to be sent to a remote location by facsimile over a telephone line.
    [17] While the color image quality achievable from scanner-printer configurations has improved, the cost of these devices has been reduced, making them more widely available and easier to access. This increased copy quality and access to the device have raised concerns about the proliferation of illegal forgery of documents such as bills, bills of exchange, identification cards, and the like. In this context, there has been concern of undesirable copying of proprietary or confidential business documents for limited distribution.
    [18] Two general classes of solutions to these problems have been developed. The first type is an "active" anti-counterfeiting system that attempts to recognize documents that should not be copied during a scanning process and, if such copy-inhibited documents are detected, prevent printing of copies. Such a system needs to first know the image characteristics of the document types that should not be copied and must reliably detect these documents when copying to them is attempted. As a result, such systems tend to be expensive, in part because accurate determination of copy-protected and copyable originals is difficult, and because the system must be programmed to recognize each type of document to be protected.
    [19] The second general class of systems is "manual" marking systems. Such systems tend to be less complicated, in part because they do not attempt to prevent copying of a given document, but print additional forensic information for every copy they produce. Often, this forensic information identifies the manufacturer, model number, serial number, or device owner of the device, allowing the source of a particular printed copy (specific system or specific individual) to be tracked. However, since most printed copies produced by the system will be perfectly legitimate documents, to avoid undesirably degrading the print quality of the copies, it is not practical for the human eye to notice forensic information. Very preferred. After all, the size, pattern, position, repetition and color of the forensic marking must be carefully designed to ensure that the marking is printed in a way that is as unobtrusive as possible. At the same time, forensic marking is easily detected and correctly interpreted to identify the device on which the copy is printed, so that when the authenticity of the document is questioned and the origin of the document must be determined, it is determined from the printed copy with near perfect accuracy.
    [20] Some previous manual marking systems print small forensic markings on blank areas of the image. However, if the print density of the page is high enough, such as when a photographic image is printed, there may not be enough extra blank space left to accommodate enough forensic marking to ensure accurate recognition. Other previous manual marking systems print forensic markings in colors (often yellow) that are not easily recognized by the human eye. As a result, these systems do not require blank image space for forensic marking, instead they can print yellow markings also in the area of the medium containing the image. However, since the image itself may already contain yellow image content, forensic marking superimposed on these areas may be compromised such that the copying device may be misrecognized if no mechanism exists to verify the marking.
    [21] Thus, forensic marking is achieved by forensic marking the printed media with a small amount of unrecognizable information superimposed on the image content, while ensuring that the manual marking system that produced the printed media can be accurately identified from the forensic marking. There is a need for a manual marking system that minimizes the impact on the system.
    [22] In a preferred embodiment, the present invention provides a visual representation of the encoded system information to the printed medium that allows the system on which the medium is printed to be subsequently identified from the medium with high accuracy, even when the marking is superimposed on other image content on the medium. Provide a forensic marking system that marks unobtrusively. Such marking systems function to suppress forgery of valuable documents by allowing counterfeit documents to be traced back to their sources.
    [23] A preferred forensic marking system has a processor that superimposes at least one forensic marking on source data representing an image to be printed. Source data may be provided in electronic form to the marking system from a data interface coupled to the processor. In some embodiments, the forensic marking system may also include a scanner coupled to the processor that acquires electronic source data by optically scanning a source image contained on the printed medium. Forensic marking includes an information marker identifying a system and a checksum marker verifying the integrity of the information marker. In addition, the system receives the combined source data and forensic marking, even if some of the source data and some of the forensic marking are printed on the same image pixel, has a low visual response to the human eye, and is easily detected by electronic scanning. And a printer coupled to the processor, which prints each forensic marking on the resulting image using a predetermined color that can be identified so that the system on which the marked image is printed is correctly identified. The marking system of the preferred embodiment uses cyan, magenta and yellow colorants to print the image by superimposing the forensic marking on yellow. The forensic marking also includes at least one position marker that places the forensic marking on the printed medium. The rectangular forensic marking of the preferred embodiment uses two position markers, where the first position marker is located at at least one corner of the marking and the second position marker is located at the corner of the marking diagonally opposite the first position marker. . In some embodiments, the forensic marking comprises at least one camouflage marker comprising a randomized data pattern to reduce the recognition of the forensic marking when the forensic marking is copied to a plurality of locations on the printed medium. It may additionally include. Recognition of forensic marking can be further reduced by rotating some of the markings on the media by multiples of 90 ° . In a preferred embodiment, the rectangular array of forensic markings is a 64 pixel x 64 pixel matrix, which consists of 64 8 pixel x 8 pixel cells. The colorant for forensic marking is placed at most 1 pixel for each of 8 pixel x 8 pixel cells. This allows the maximum density of forensic markings in the rectangular array to be approximately 1.5%, which avoids significant degradation of image quality. In a preferred embodiment, forensic marking is copied at 256 pixel-row and pixel-column intervals on the printed medium. In addition, adjacent forensic markings are offset from each other by one pixel-row.
    [24] The invention may also be embodied as a method of printing a forensic marked image with a printer. Forensic marking is printed using a predetermined color, such as yellow, to identify the system, which is difficult to detect by the human eye but can be easily detected by electronic scanning. Such a method encodes system information identifying a printer into an information marker, calculates a checksum for the information marker, encodes the checksum into a checksum marker, and sources at least one encoded forensic marking that includes the information marker and the checksum marker. Overlaid on the data to generate forensic marked output data, and then the output data is printed on the print medium. In some embodiments, the method of the present invention also adds, for each forensic marking, at least one position marker that identifies the position and rotation of the corresponding marking on the print media. In addition, the forensic marking may include at least one camouflage marker that includes a randomized data pattern, thereby reducing the visibility of the forensic marking copied onto the printed medium. When a printer prints a swath of an image on a medium, the method of the present invention can be implemented by obtaining a swath of image data for a source image, and the threshold of the swath of the image data is greater than the threshold. When there is a lot of color data, it can be implemented by a method of superimposing a swath of at least one forensic marking having an image pixel pattern encoded in the image data in a graphic form. The method of the present invention then prints the image data on the medium to produce a forensic marked image. This method can be repeated until all swaths of image data have been printed. Typically this method will be performed by a processor of the printing system.
    [25] Yet another embodiment of the present invention is a system for determining a device on which a printed medium is printed. The system of the present invention comprises a media receptor for receiving a printed medium, an image scanner in optical communication with a media processor for obtaining multicolor image data for the printed medium, and an image scanner coupled to the image scanner from the multicolor image data. And a color separation unit for separating the predetermined color image data, and a forensic identification unit that is connected to the color separation unit and identifies the forensic marking in the predetermined color image data located on the medium printed by the apparatus when the medium is printed. The forensic identification unit locates subsystems that place individual forensic markings on predetermined color image data, verification subsystems that analyze individual forensic markings to verify their integrity, and analyze devices for which printed media are printed by analyzing individual forensic markings. It has an identification subsystem that identifies it.
    [26] Yet another embodiment of the present invention is a method of determining a printing device on which a forensic marked print image is printed. The printed image is color separated to separate the image data with respect to the predetermined color on which the marking is printed, and then the image data is scanned to position the forensic marking. The checksum for the encoded information marker is calculated and then compared to the printed checksum obtained by decoding the checksum marker. If the calculated checksum and printed checksum match, then the validity of the particular forensic marking is guaranteed, and the information marker is decoded to determine the printing device on which the image was printed. If the two checksums do not match, another forensic marking is placed and analyzed for validity.
    [27] In another embodiment, the information marker of the forensic marking may alternatively or additionally indicate whether copying of the forensic marked image is acceptable or prohibited. If the printing system determines that it includes forensic marking with an information marker indicating that the source image should not be copied, the printer will be disabled and no printed copy will be created.
    [28] Other features and advantages of the invention will become apparent from the following detailed description, which illustratively illustrates the principles of the invention, with reference to the accompanying drawings.
    [1] 1 is a schematic diagram of a manual marking printing system embodying the present invention,
    [2] 2A shows an exemplary source image associated with the manual marking printing system of FIG. 1, FIG.
    [3] FIG. 2B shows an example output image generated by the manual marking printing system of FIG. 1, for the example source image of FIG. 2A;
    [4] 3 is a schematic representation of forensic marking produced by the printing system of FIG.
    [5] 4 is a schematic illustration of a copy of a forensic marking produced by the printing system of FIG. 1 on a printed output medium, indicating the location of multiple markings on a medium; FIG.
    [6] 5 is an enlarged view of an exemplary forensic marking produced by the manual marking printing system of FIG. 1, FIG.
    [7] FIG. 6 is a schematic illustration of a copy of a forensic marking produced by the printing system of FIG. 1 on a printed output medium, illustrating exemplary orientation of different markings on a medium; FIG.
    [8] 7A-7C schematically illustrate colorants disposed in a four pixel portion of forensic marking added to an exemplary image printed by the system of FIG. 1, FIG.
    [9] 8 is a perspective view of an all-in-one scanner / printer / copier device incorporating the manual marking printing system of FIG.
    [10] 9 is a perspective view of a color swath printer incorporating the manual marking printing system of FIG.
    [11] FIG. 10 is a flowchart of a method of printing a forensic marked image on a print medium 16 using the color swath printer of FIG. 9.
    [12] Explanation of symbols for the main parts of the drawings
    [13] 20: forensic marking 30: processor
    [14] 40: scanner 50: printer
    [29] Referring to the drawings, in particular FIGS. 1, 2A and 2B, configured to add an encoded forensic marking 20 capable of identifying the printing system 10 to an output image 14 printed on a medium according to the invention. A manual marking printing system 10 is shown. The system 10 ensures that the system 10 that produced the printed medium 16 can be identified with high accuracy from the forensic marking 20 on the printed medium 16, while providing a small amount of superposition on the image content. By marking unrecognized information on the printed medium 16, the effect of these forensic markings 20 on print quality is preferably minimized.
    [30] The preferred embodiment of the printing system 10 superimposes at least one forensic marking 20 having a pattern of image pixels encoded in graphic form on the source data, thereby output data corresponding to the forensic marked output image 14. It includes a processor 30 for generating a. Preferably, the source data is in electronic form via data interface 12 or from optical scanner 40 electrically connected to processor 30 to obtain processor 30 from source image 18. Can be provided. The construction and operation of optical scanners are well known to those skilled in the art, for more details see the Hewlett Packard Journal ["Designing a Scanner with Color Vision" (August 1993, page 52), "Design of a 600-Pixel-per -Inch, 30-Bit Color Scanner "(February 1997, page 54), which are incorporated herein by reference. In addition, the preferred embodiment includes a printer 50 electrically connected to the processor 30 to generate forensic marked images 14 by outputting output data. As will be described in more detail, forensic marking 20 uses a color that the human eye has a low visual response but can be easily detected by electro-optical scanning, so that a predetermined position on the forensic marked image 14, Printed at intervals and directions. A preferred embodiment of the printer 50 is a color inkjet printer that includes a print mechanism 52 that uses cyan, magenta, yellow and black colorant print cartridges 54 to print the color image 14. Typically, the color inkjet printer 50 swashes horizontal portions or swaths of the image 14 on the print medium 16 as the print cartridge 54 is scanned across the surface of the medium 16 in the scan direction 2. Print The construction and operation of color inkjet printers are well known to those skilled in the art and are described in Hewlett Packard Journal [Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No. 1 (February 1994), which are incorporated herein by reference. In a preferred embodiment, yellow colorants are used to print all forensic markings 20, especially when printed on a white or pale color background, since the human eye is less sensitive to yellow color. As will be described in more detail below, because optical scanning performs color separation, portions of the forensic marking 20 may be superimposed on the output image even in an area that also includes a portion of the source image.
    [31] Now, considering the layout of the forensic marking 20 in more detail, and referring to FIGS. 3, 4 and 5, each forensic marking 20 of the preferred embodiment is an 8 row by 8 column matrix of 64 cells, such as cell 28. It is configured as. Further, each cell 28 is preferably configured as an 8 row by 8 column matrix of 64 pixels, such as pixel 62. Therefore, each marking 20 is a 64 pixel-row x 64 pixel-column matrix. Each pixel 62 is a programmatically selectable printable position on the medium 16. In addition to using a yellow colorant, the recognition of the marking 20 for the human eye is by printing each marker cell 28 as a sparse matrix with a colorant that overlaps at most one of the 64 pixels in each cell 28. Is further reduced. Preferably, this pixel is located at the same location in each cell, for example the upper left corner, to provide a uniform space between the marked pixels. Thus, the maximum print density of forensic marking in rectangular arrays is approximately 1.5%. In a preferred embodiment of a color inkjet printer, two drops of yellow ink are used as colorant for one pixel.
    [32] While the embodiment of a single drop per cell described above is preferred, the present invention may also contemplate placing additional drops per cell to allow more complex encoding patterns at the cost of increased print density.
    [33] Now, considering the content of the forensic marking 20 in more detail, each forensic marking 20 includes a plurality of markers. Each forensic marking 20 includes an information marker 22 representing the system 10 and a checksum marker 24 representing the information marker 22. In addition, each forensic marking 20 includes at least one position marker 26 that positions and orients the marking 20 on the printed medium 16 as described in more detail below. Each marker 22, 24, 26 spans one or more cells 28. The cells 28 of the marker may all be contiguous, or the marker may be divided into two or more sections of cells 28. Each marker 22, 24, 26 is printed in graphic form on the medium 16 as an encoded cell pattern.
    [34] In a preferred embodiment, the information marker 22 contains sufficient information to identify with a very high degree of certainty the system 10 that printed the output medium. The identification information may include any of the manufacturer, model number, serial number, buyer or owner information of the printing system 10. This information is encoded in marker 22 and printed using a particular binary code. The information marker 22 of the preferred embodiment includes a machine type identifier section 22a for encoding the type of system 10 and a machine serial number identifier section 22b for encoding the serial number of the system 10. If copy-protected source images, such as banknotes, are illegally copied, high accuracy system 10 identification is important to avoid misidentifying the suspected counterfeiter. The checksum marker 24 provides redundancy, enabling high accuracy identification to ensure that all pixels of the marking that contain the information are correctly printed. In a preferred embodiment, checksum marker 24 encodes the total number of cells used to encode information marker 22. For example, in the exemplary forensic marking 20 of FIG. 5, 12 cells 28 are printed from 32 total cells in the serial number section 22b of the information marker. Thus, 12 corresponding binary code values are encoded in the checksum marker 24 (where cell 25a represents the least significant bit of the checksum and cell 25b represents the most significant bit of the checksum). When the printed forensic marking 20 is analyzed to identify the system 10, the checksum marker 24 is compared with the decoded information marker 22. If the two do not match, the current marking 20 is ignored and the other marking will be decoded instead.
    [35] In another embodiment of the present invention having the characteristics of an active anti-counterfeiting system, the information marker 22 may include a "do not copy" control flag in place of or in addition to identifying information. In the following, the copier operation in detecting such a control flag will be described.
    [36] Considering now at least one position marker 26 in more detail, the marker 26 includes a notable pattern that allows the position of the corresponding forensic marking 20 to be accurately determined. In a preferred embodiment, position marker 26 comprises a 2 x 2 cell matrix. In addition, each forensic marking 20 of the preferred embodiment is a diagonal of the forensic marking 20 from two position markers 26, i.e., a starting position marker 26a located around one corner of the forensic marking and a starting position marker 26a. Has end position markers 26b having different encoding patterns located around opposite corners. The end marker 26b includes four cells having the same pattern, and the start marker 26a has three cells and one blank cell having the same pattern. Forensic by placing two different position markers at opposite corners and ensuring that the four cells at each of the other two corners of the forensic marking 20 do not contain a start marker 26a or end marker 26b pattern. The marking 20 can be easily identified by electronic scanning on the media receptor 42 of the scanner 40 regardless of the orientation of the source image 18.
    [37] Now consider the position of the forensic marking 20 on the forensic marked image 14, and as best understood with reference to the example of FIG. 4, the markings 20a, 20b, and 20c in the preferred embodiment. Marking 20 is copied at a predetermined position, spacing and direction, provided in plural, thereby providing redundancy to improve the accuracy of the printing system 10 decision if some marking 20 is compromised, and forensic It is ensured that the marking 20 is not easily removed from the print media 16 prior to subsequent copying to invalidate the marking scheme. As will be described in more detail below, overlapping portions of the forensic marking 20 in the area of the output image 14 that also include portions of the source image 18 do not remove the corresponding portion of the source image 18. It further reduces the ability to remove the forensic marking 20. The copied markings 20a, 20b, 20c are located at predetermined pixel-row spacing 62 and pixel-column spacing 64 with respect to each other. As shown in the preferred embodiment and in FIG. 4, the pixel-column spacing 64 is 256 pixels, which is equivalent to a 32 cell-column spacing. The pixel-row spacing 62 is at least 256 pixels (32 cell-rows), i.e., in a preferred embodiment, some individual pixel-row spacing 62 divides the forensic marking 20 between adjacent horizontal swaths. May be increased as a requirement to avoid doing so. Horizontally adjacent forensic markings are offset from each other by a predetermined number of pixel-rows. The preferred embodiment uses pixel-row offset 66. In addition, vertically adjacent forensic markings are offset from each other by a number of pixel-columns. In a preferred embodiment, the pixel-column offset 67 is randomized for different horizontal swaths of the printed medium 16, forensic marking that can make the marking 20 more recognizable to the human eye. Minimize the patterning of 20. Using the present invention, it is possible to select predetermined or randomized pixel-row and pixel-column spacings and offsets.
    [38] Yet another embodiment utilizes an additional mechanism to further reduce the visual perception of the same radiant forensic markings 20a to 20h. As best understood with reference to FIG. 6, some forensic markings 20 may be printed in a direction rotated substantially by multiples of 90 ° from any other forensic marking 20. In the example of FIG. 6, each forensic marking 20a-20h is rotated by 90 ° from the adjacent markings 20a-20h in both the scan direction 2 and the media travel direction 4. Other rotational states may alternatively be used, such as randomly selecting multiples of 90 [ deg.] Rotation for each adjacent marking 20a-20h. The forensic marking 20 also includes at least one camouflage marker 29 that can be used to further reduce the visual perception of the same radiant forensic markings 20a to 20h. Each camouflage marker 29 has one or more cells that do not contain location, checksum or system information. In a preferred embodiment, these cells are left blank to minimize the print density of the marking 20, but in another embodiment they may be printed with random data to make at least some of the forensic markings 20a to 20h different. . 3 and 6 also show a forensic marking 20 having two camouflage markers 29 positioned as shown, according to the present invention different numbers and positions within the forensic marking 20. Camouflage markers 29 may be considered.
    [39] Considering the superposition of the forensic marking 20 on the source image 18 in more detail now and referring to the exemplary marking patterns of FIGS. 7A, 7B, and 7C, the four pixel portions 70a-c of the forensic marking cell 28 are described. Three examples of are described. The upper left pixel 62a of each cell portion 70a-c represents a pixel of the cell 28 where a yellow colorant may be placed to form the forensic marking 20, and the remaining pixels 62b-d are forensic. No colorant for marking 20 will be received. All four pixels of the cell portions 70a-c may be printed using the appropriate combination of cyan, magenta, yellow and black colorants as required to make the source image 18. The cell portion 70a represents the case where the source image is blank in this portion. In this case, if cell 28 is forensic marked, two drops of yellow colorant (indicated by the two rectangular markings) are placed into pixel 62a. The cell portion 70b shows the case where the source image contains cyan and magenta data in this portion. In this case, if cell 28 is forensic marked, two drops of yellow colorant (indicated by two rectangular markings) are placed into pixel 62a, as well as magenta and cyan drops (indicated by circular markings). The cell portion 70c represents a case where the source image contains yellow data in this portion. In this situation, no yellow forensic marking colorant will be added to the source image.
    [40] As will be described later, optical scanning can electronically separate the yellow markings from cyan and magenta markings, thus forensic marking even when the forensic marking 20 is superimposed on an area of the source image containing cyan or magenta colorants. Can be detected. However, if the marking 20 overlaps on an area containing a yellow (or black including yellow) colorant, the disparate yellow data in the scanned image will undermine the forensic marking 20. If the position marker 26 is broken, the forensic marking may not be located at all. The position marker 26 is valid, but if the information marker 22, the checksum 24, or both are compromised, it is certain that the checksum marker will not match the decoded information marker 22, so that the tampering characteristics of the marking are Will be detected to avoid misrecognition of the printing system 10.
    [41] Considering an alternative packaging configuration for the printing system 10 of the present invention, and referring now to FIG. 8, the present invention provides an " all-in-one " that integrates a scanner 40, a processor 30 and a printer 50. Can be implemented in the device 6 to function as a standalone copier that can be operated from the control panel 44. The apparatus 6 also includes a data interface 12 for receiving source data in electronic form corresponding to the source medium 17 including the copied source image 18. The scanner 40 may take the form of a flatbed scanner (shown) in which the source image 18 is located in a fixed position on the media receptor 42 and the optical scanning component moves relative to the media 17. have. Alternatively, scanner 40 may take the form of a sheet-feed scanner (not shown) in which the optical scanning component is fixed and medium 17 moves relative to the scanning component. Alternatively, as best understood with reference to FIG. 9, the present invention is implemented in a printer 8 that does not include a scanner 40 but integrates a processor 30, a printer 50, and a data interface 12. Can be. In operation, printer 8 receives, in electronic form, source image 18 to be printed from a device, typically a computer, connected to data interface 12. In another alternative embodiment of printing system 10, scanner 40 and printer 50 are packaged separately and connected to a computer (not shown) having processor 30. The above described configuration is one example of the present invention, but the scope of the present invention is not limited only to these configurations.
    [42] In addition, the present invention can be implemented as a novel method of printing a forensic marked image on a print medium 16 using a color swath printer. The forensic marking 20 added to the source image 18 to be printed consists of a graphic pixel pattern formed by an arrangement of markers, each marker having a graphic pixel pattern. As best understood with reference to FIG. 10, the method provides information marker 22 with sufficient printing system information to identify the system 10 on which the print media 16 has been printed, as previously described herein. It begins with encoding S102. Then, the checksum for the information marker 22 is calculated (S104). Preferably, the checksum is the total number of cells 28 printed for encoding system information. For example, the information marker 22 of the forensic marking 20 of FIG. 3 has 32 possible cells that can be printed to represent system information, so the checksum will have a value in the range of 0-32. According to the method of the invention, this checksum value is itself encoded with a checksum marker 24 (S106). The start 26a and end 26b position markers that define the area covered by the forensic marking 20 are defined (S108), each of which has a different characteristic graphic pixel pattern for easy identification. Then, a graphical pixel pattern for the forensic marking 20 is defined by the start 26a and end 26b markers that delimit the area comprising the information marker 22, the checksum marker 24, and the camouflage marker 29. (S110), the content may be determined dynamically at the time of printing in some embodiments to reduce visual recognition of the forensic marking 20 due to copying on the print media 16. FIG. After the forensic marking pattern is formed, the method of the present invention obtains a swath of the source data corresponding to the source image 18 in step S112. Whether or not the forensic marking 20 is added to the source data for printing depends on whether color data exists in the source data for the swath. In a preferred embodiment, if there is no color data in the swath, using only black colorants to improve printing throughput (since typically printing black data requires little scanning to completely print the swath) The swath will then be printed, so taking the "no" branch of step S114 will omit the forensic marking 20 from overlapping on the source data for the swath. Similarly, if the swath contains less than 64 pixels of data in the scan direction 2, taking the "no" branch of step S116 likewise indicates that the forensic marking 20 overlaps on the source data for the swath. Omitted, only partial forensic marking 20 in the swath is not printed. However, if the swath contains color data ("Yes" branch of step S114) and the corresponding color is 64 pixels or more in the scanning direction 2 ("Yes" branch of step S116), preferably yellow At least one forensic marking 20 is superimposed on the source data for the swath using the colorant (S122) to form an output data swath for printing (S124) on the print medium. If further source data to be printed as another swath remains (YES branch of step S126), the method will obtain the next swath of source data (S112). If the source data to be printed no longer remains (NO branch in step S126), the method ends. In some embodiments, forensic marking 20 for a given swath may be further modified prior to printing. In step S118, randomized data may be inserted into the camouflage marker 29 to reduce the recognition of the marking 20. Alternatively or additionally, each forensic marking 20 in the swath may be rotated S120 by a multiple of 90 ° , which may also reduce the recognition of the marking 20.
    [43] As best understood with reference to FIG. 1, processor 30 performs the methods described above, including modules that may be implemented in hardware, firmware, software, or any combination thereof. The forensic marking unit 31 receives the system information 32 and source data, and performs the calculation, encoding, randomization, rotation, and superposition required to form the forensic marking 20 in the output data sent to the printer 50. Perform.
    [44] Another aspect of the invention involves the inspection of forensic marking 20 printed on a particular source medium 17. As best understood with reference to FIG. 1, the present invention is embodied as a system 10 that identifies, through a forensic marking 20 printed on a medium 17, a printing device on which a particular medium 17 is printed. Can be. The medium 17 is positioned on the medium receptor 42 and scanned by the scanner 40 to obtain multicolor electronic source data corresponding to the source image 18. In general, the source data represents the primary colors red, green and blue. Processor 30 processes the source data. Processor 30 has a color separation unit 33 coupled to image scanner 40 for converting and separating primary color image data into a data plane for each secondary color, cyan, magenta and yellow. The processor also has a forensic identification unit 34 connected to the color separation unit 33 and receiving yellow color plane image data from the separation unit 33. The forensic identification unit 34 has a locator module 35 that scans the yellow color plane data to locate data indicative of the forensic marking 20 therein. In addition, the forensic identification unit 34 analyzes each forensic marking 20 by calculating a checksum for the information marker 22 of the marking 20 and decodes the checksum marker 24 to determine the printed checksum. And a verification subsystem for comparing the calculated checksum with the printed checksum, and if the checksums match, the analyzed forensic marking 20 is valid. The forensic identification unit 34 also has an identification module 36 for decoding the information marker of the verified forensic marking 20 to determine the printing device on which the source medium 17 is printed.
    [45] Another embodiment of the present invention relating to the inspection of forensic marking printed on a particular source medium 17 is a printing system that modifies the behavior when copy prohibitions are detected. As described above, the information marker 22 may include a "copy prohibited" control flag. In this embodiment, the forensic identification unit 34 analyzes the forensic marking 20 while copying the document, and if the decoded information marker 22 indicates that the source image 18 should not be copied, the system ( 10) will not produce a copy. This capability is very useful with controlled copy documents where unauthorized copying is prohibited. By superimposing the information markers 22 thereon when the original document is printed, the original document will be prevented from being copied later on the system 10.
    [46] From the foregoing, the printing systems and methods provided by the present invention represent a major advance in the art. The printer is configured in accordance with the present invention to provide a forensic marking system for unobtrusively marking encoded system information for a printed medium. The encoded system information can then identify with high accuracy the system on which the medium is printed, even if the marking is superimposed on other image content. Although some specific embodiments of the invention have been described and illustrated, the invention is not limited to the specific methods, forms, or apparatus of the parts so described and illustrated. In particular, the present invention relates to a one-pass swath printer in which a swath is fully printed during one pass of the printhead 54 through the print medium 16, or through the print medium 16 to completely print the swath. Multiple passes of the printhead 54 can be used with a multi-pass swath printer that requires it. The present invention can be used with any type of swath printer, including band printers and drum printers. The invention is practiced as inkjet printers of all types, including printers using thermal and piezo printing techniques, and as non-swath or non-inkjet color printers, such as color laser printers. Can be. The invention is limited only by the claims.
    [47] According to the present invention, it is possible to provide a forensic marking system and method for identifying a printing apparatus on which a medium is printed. Encoded forensic marking that identifies the device but is less perceptible to the human eye is superimposed on the printed image. Marking has a color, size, density, and repeating pattern, which provides a very accurate identification of the printing device, even if the printed media contains high density image content, while only minimally affecting print quality.
    权利要求:
    Claims (10)
    [1" claim-type="Currently amended] As a method for printing a forensically marked image 14 to a printer 50,
    Encoding system information 32 identifying the printer 50 into information markers 22a-b (S102);
    Calculating a checksum for the information markers 22a-b (S104);
    Encoding the checksum with a checksum marker 24 (S106);
    In order to generate output data corresponding to the forensic marked image, at least one encoded forensic marking 20 comprising the information markers 22a-b and the checksum marker 24 is placed on the source data. Overlapping with (S122),
    And printing (S124) the output data on a printer medium 16 to produce the forensic marked image,
    The at least one forensic marking 20 is printed using a predetermined color that is difficult to detect by the human eye and easily detectable by electronic scanning to identify the system.
    How to print.
    [2" claim-type="Currently amended] The method of claim 1,
    Adding to each of the at least one forensic marking 20, at least one position marker 26a-b indicating the position of the forensic marking 20 on the print medium 16 (S108).
    How to print.
    [3" claim-type="Currently amended] The method of claim 2,
    The at least one position marker 26a-b further indicates the orientation of the forensic marking 20 on the print medium 16.
    How to print.
    [4" claim-type="Currently amended] The method of claim 1,
    Printing the output data (S124),
    Print the source data using at least one of cyan, magenta and yellow colorants,
    Further comprising printing the at least one forensic marking 20 using a yellow colorant.
    How to print.
    [5" claim-type="Currently amended] The method of claim 1,
    The method may further include rotating (S120) at least a portion of each of the at least one forensic marking 20 by a multiple of 90 ° before the printing step S124.
    How to print.
    [6" claim-type="Currently amended] The method of claim 1,
    At least one camouflage marker representing randomized data for each of the at least one forensic marking 20, such that the visibility of the forensic marking 20 due to copying on the print medium 16 is reduced. Adding (S118) further includes (29)
    How to print.
    [7" claim-type="Currently amended] A system (10) for printing forensic marked images,
    A processor 30 superimposing at least one forensic marking 20 on the source data to produce output data corresponding to the forensic marked image 14—the at least one forensic marking 20 is configured in the system. (10) has an information marker (22a-b) and a checksum marker (24) that is closest to the information marker (22a-b) and represents the information marker (22a-b);
    A printer 50 connected to the processor 30 to print the output data to generate the forensic marked image 14,
    The at least one forensic marking 20 is printed with a predetermined color that has a low visual response to the human eye and can be easily detected by electronic scanning to identify the system 10.
    Printing system.
    [8" claim-type="Currently amended] The method of claim 7, wherein
    The forensic marking 20 is rectangular,
    The forensic marking 20 may include a first position marker 26a positioned at one corner of the forensic marking 20 and a diagonally opposite corner of the forensic marking 20 from the first position marker 26a. Has a different second position marker 26b located at
    The first and second position markers 26a and 26b commonly indicate the position and direction of the forensic marking 20.
    Printing system.
    [9" claim-type="Currently amended] The method of claim 7, wherein
    The information markers 22a-b indicate that copying of the forensic marked image 14 is prohibited,
    A scanner 40 coupled to the processor 30 to obtain the source data from a source image 18;
    Detection means connected to the scanner 40 to detect whether the source image 18 contains copy prohibited content;
    Control means responsive to the detection means and connected to the printer 50 to disable copying of the copy prohibition content;
    Printing system.
    [10" claim-type="Currently amended] A system (10) for determining a device on which a printed medium (17) is printed,
    A media receptor 42 for receiving the printed media 17;
    An image scanner 40 in optical communication with the medium receptor 42 to obtain multicolor image data 18 for the printed medium 17;
    A color separation unit 33 connected to the image scanner 40 to separate predetermined color image data from the multicolor image data 18;
    A forensic identification unit 34 connected to the color separation unit 33 for identifying at least one forensic marking 20 located on the printed medium 17 by the apparatus in the predetermined color image data. The forensic identification unit 34 analyzes the forensic marking 20 and a locator subsystem 35 for placing each of the at least one forensic marking 20 into the predetermined color image data. A verification subsystem 37 for verifying its integrity, and an identification subsystem 36 for analyzing each respective forensic marking 20 to identify the device on which the printed media 17 is printed. Containing
    Device determination system.
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    同族专利:
    公开号 | 公开日
    TWI231788B|2005-05-01|
    US7002710B1|2006-02-21|
    CN1317763A|2001-10-17|
    GB0108633D0|2001-05-30|
    CN1183477C|2005-01-05|
    KR100793519B1|2008-01-14|
    GB2361211A|2001-10-17|
    GB2361211B|2003-12-31|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2000-04-10|Priority to US09/546,247
    2000-04-10|Priority to US09/546,247
    2001-04-09|Application filed by 파트릭 제이. 바렛트, 휴렛-팩커드 컴퍼니(델라웨어주법인)
    2001-10-19|Publication of KR20010090779A
    2008-01-14|Application granted
    2008-01-14|Publication of KR100793519B1
    优先权:
    申请号 | 申请日 | 专利标题
    US09/546,247|US7002710B1|2000-04-10|2000-04-10|High reliability forensic color marking system|
    US09/546,247|2000-04-10|
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